In the latest edition of the scientific journal Nature, physicists at the University of Vienna and the Austrian Academy of Sciences report that they have achieved quantum (light) teleportation over a record distance of 143 km. The previous record of 97km was set in China a few months ago. The experiment is a major step towards satellite-based quantum communication.
This research does not, of course, mean that we humans will be teleported any time soon—if ever.
The team of international researchers, led by Austrian physicist Anton Zeilinger, transmitted quantum states between the two Canary Islands of La Palma and Tenerife. The goal, however, was not to break the distance record (set by ) but help create a “quantum internet” that would allow greater communications security.
“Our experiment shows how mature ‘quantum technologies’ are today, and how useful they can be for practical applications,” says Zeilinger. “The next step is satellite-based quantum teleportation, which should enable quantum communication on a global scale. We have now taken a major step in this direction and will use our know-how in an international cooperation, which involves our colleagues at the Chinese Academy of Sciences. The goal is to launch a ‘quantum satellite mission’.”
Xiao-song Ma, one of the experiment’s researchers, says, “The realization of quantum teleportation over a distance of 143 km has been a huge technological challenge.” The Max Planck Institute for Quantum Optics in Garching (Germany) and a University of Waterloo (Canada) experimental group aided the researchers in their record-setting experiment. (Max Planck, it should be noted, is the originator of quantum theory, and the namesake of Planck’s Constant.)
“An important step for our successful teleportation was a method known as ‘active feed-forward’, which we have used for the first time in a long-distance experiment,” says Ma. “It helped us to double the transfer rate.” Active feed-forward allows conventional data to be sent alongside quantum data. The recipient of the transmission can then decipher the signal with greater efficiency.
The next step? Quantum satellite communication.
“Our latest results are very encouraging with a view to future experiments in which we either exchange signals between Earth and satellites or send messages from one satellite to another,” says Rupert Ursin, Zeilinger’s colleague. ”In satellite-based experiments, the distances to be travelled are longer, but the signal will have to pass through less atmosphere. We have now created a sound basis for such experiments.”